Are the kids not living with her father? Is there any real danger social services would take the kids away to a group/foster home if the grandfather was in the picture and considered to be a responsible person? Unless the father or fathers of the kids were actively trying to get custody of the kids?
I am grateful to say that I don't know that much about how that kind of thing works. Let's assume that Mangum is the custodial parent, and that Mangum is living with her father (which legally is not the same as the kids living with their grandfather). Looking at Mangum's record, I HOPE social services was on her case. It could be that the kid's father has been trying to get custody or that social services was telling Mangum that one more arrest and the grandfather would be given custody or the kids put in a foster home.
"Women don't lie about rape" is what you hear from some quarters. I'll bet they do if it's the only way they can avoid losing their kids. And the funny thing is that even a Durham jury would buy the explanation as a reason for a false accusation.